Fritz Adalis15h ago
Buttered Jorts

Hey #devops #git peeps, mind if I pick your brains for a bit?

I maintain a couple of internal GitHub repos at $Employer for various windows app install scripts (PowerShell), that are used to deploy our EDR, DLP, and other such tools. These all grew out of a script template (or if I’m feeling fancy, framework) that was meant to abstract away some differences in behavior between a couple legacy MDM platforms and our planned future platform.

Changes to these scripts fall into three gross categories:

  • Bumps of the app version, generally without any other changes.
  • Changes to the template logic.
  • Changes to the app-specific logic.

    • I’m gonna skip version changes, because they’re essentially a subclass of app-specific logic.

    My workflow in developing the template generally goes something like this:

  • Work on an app-specific logic change.
  • Determine this is actually something more broadly usable than just that one app, and move the change out of the app-specific logic and into the template logic.
  • Increment the template version in the front-matter of the app-specific script.
  • Diff the app-specific script against the template, and merge in the changes in the template logic, ignoring the app specific logic (actual logic in the app script, placeholder in the template)
  • Diff the updated template script against each of the other app-specific scripts, and merge in the template logic, ignoring the app-specific logic (placeholder logic in the template, actual logic in the app script).

    • What I’m interested in is automating step 5, so that on push of an updated template version, all my scripts update too. Automating step 4, so that on push of an app-specific script containing updated template logic, the template repo gets updated would be pretty cool too.

    What I don’t understand is how I could programmatically merge in only the desired changes (template logic) , and not undesirable ones (app-specific logic)?

    12:17amWeb
    Show threadFritz Adalis15h ago
    @ajn142
    Can you move app-specific logic to another file?
    Show threadButtered Jorts14h ago
    @FritzAdalis maybe? The hard part of any change is validating it against the handful of systems it supports now.
    Show threadFritz Adalis14h ago
    @ajn142
    Either that or put the app specific code in another file in the repo and 'compile' it back into the main file for deployment.
    Show threadButtered Jorts14h ago
    @FritzAdalis that may be an option, though the linter will throw an absolute fit about the app-specific code calling functions that aren’t declared (because they come from the template file)
    Show threadFritz Adalis14h ago
    @ajn142
    Build before linting?
    Show threadButtered Jorts14h ago
    @FritzAdalis you mean tolerate the linter errors in my IDE while developing the code?
    /le shock
    Show threadFritz Adalis14h ago

    @ajn142
    I suppose that's a drawback.

    Make it a module and import-module ./filename.psm1? Thinking about it that seems like it'd be the mostest correctest.

    Show threadButtered Jorts14h ago
    @FritzAdalis I’m really not trying to be obtuse, these convos are giving me some good things to think about. Doesn’t sound like there’s a magic bullet within git’s diff functionality to accomplish this… maybe if i made an archive branch to hold the commit history up-to today, rebased the main branches off the template repo, then force-pushed, so that now the derivative repos would share a commit history with the template, and there would be commits setting the app-specific properties newer than the commit history from the template?
    Show threadFritz Adalis14h ago
    @ajn142
    Maybe a branch per app and merge in changes? That'd be a hassle though I think.